Control parameter optimizing system that optimizes values of control parameters of an existing power plant and operation control optimizing apparatus equipped therewith

ABSTRACT

A control parameter optimizing system and an operation optimizing apparatus equipped therewith are provided, the system being applicable to an existing plant without modifying the control panel or equipment of the plant, the system further being capable of optimizing the operation control of the plant in accordance with diverse operational requirements. The system includes an objective function setting section, a plant model, and a control parameter optimizing section. The control parameter optimizing section includes an optimization control parameter selecting section and an optimization control parameter adjusting section. The optimization control parameter selecting section selects as an optimization control parameter the control parameter for optimizing an objective function based on control logic information extracted from a power plant. The optimization control parameter adjusting section adjusts the value of the optimization control parameter using the plant model in such a manner as to optimize the objective function.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an apparatus for optimizing theoperation control of a power plant or an industrial plant.

2. Description of the Related Art

There have been developed control technologies for improving the plantoperability, particularly of a thermal power plant. The technologiesinclude those for enhancing load following capability or shorteningstart-up time, etc., to stabilize an electric power system in responseto fluctuations in the supply of renewable energy or in the demand forpower.

JP-2007-255198-A discloses an optimum operation system which, used in anenergy plant combining boilers, turbines and generators, determines theamount of steam generated by each boiler and the amount of steam andthat of oil steam distributed to each turbine (the amounts are calledcontrol parameters) in such a manner as to minimize the total energycost (improvement item) of the plant based on a characteristic model ofeach of the devices constituting the plant.

SUMMARY OF THE INVENTION

The optimum operation system described in the above-cited patentapplication presupposes that the specifications of the control panel atthe power plant are already known and so are the operationalrequirements for the plant. For this system, the control parameters andimprovement items are limited. However, the specifications of thecontrol panel for the power plant differ from plant manufacturer toplant manufacturer and from equipment to equipment. The operationalrequirements for the power plant also vary depending on the country andthe locality. Thus one problem with this optimum operation system isthat it cannot support the various control panel specifications anddiverse operational requirements in a one-size-fits-all manner; powerplants having different control panel specifications or differentoperational requirements typically require their control panels or theirequipment to be modified.

The present invention has been made in view of the above circumstances.An object of the present invention is to provide a control parameteroptimizing system and an operation optimizing apparatus equippedtherewith, the system being applicable to an existing plant withoutmodifying the control panel or equipment of the plant, the systemfurther being capable of optimizing the operation control of the plantin accordance with diverse operational requirements.

In solving the above problems and according to one embodiment of thepresent invention, there is provided a control parameter optimizingsystem including: an objective function setting section that sets anobjective function to be optimized in controlling the operation of aplant; a plant model that simulates the operation of the plant andcalculates a process amount of the plant and the objective function; anda control parameter optimizing section that optimizes the values ofcontrol parameters of the plant using the plant model in such a manneras to optimize the objective function. The control parameter optimizingsection includes: an optimization control parameter selecting sectionwhich, based on control logic information extracted from the plant,selects as an optimization control parameter the control parameter foruse in optimizing the objective function; and an optimization controlparameter adjusting section that adjusts the value of the optimizationcontrol parameter using the plant model in such a manner as to optimizethe objective function.

According to the present invention, it is possible to optimize theoperation control of an existing plant regardless of the plant type orcontrol panel specifications and without recourse to modifying thecontrol panel or equipment of the plant.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram showing a configuration of a control parameteroptimizing system according to a first embodiment of the presentinvention;

FIG. 2 is a schematic view showing control logic information to beinputted to an optimization control parameter selecting section of thecontrol parameter optimizing system according to the first embodiment;

FIG. 3 is a block diagram showing a configuration of an operationcontrol optimizing apparatus equipped with the control parameteroptimizing system according to the first embodiment;

FIGS. 4A and 4B are schematic views showing typical display of optimumsolutions for two cases, one case being one in which start-up time andlifetime are set as the objective functions, the other case being one inwhich start-up time, lifetime consumption, and fuel cost are set as theobjective functions;

FIG. 5 is a schematic view showing another typical display of theoptimum solutions for the case in which start-up time and lifetimeconsumption are set as the objective functions;

FIG. 6 is a block diagram showing a configuration of an operationcontrol optimizing apparatus according to a second embodiment of thepresent invention; and

FIG. 7 is a schematic view showing an example a typical relation betweenmultiple optimum solutions and a plant operation limiting value for thecase in which start-up time and lifetime consumption are set as theobjective functions and an upper limit of the lifetime consumption isset as the plant operation limiting value.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Some preferred embodiments of the present invention are described belowwith reference to the accompanying drawings. Throughout the drawings,like reference numerals designate like or corresponding parts, and theirdescriptions will be omitted hereunder where redundant.

First Embodiment

FIG. 1 is a block diagram showing a configuration of a control parameteroptimizing system according to a first embodiment of the presentinvention. In FIG. 1, the control parameter optimizing system 100includes an objective function setting section 1, a control parameteroptimizing section 2, a plant model 3, a control parameter settingsection 4, a physical parameter setting section 5, and a designparameter setting section 6.

The objective function setting section 1 sets the objective functionsinputted by an operator to the control parameter optimizing section 2.The objective functions in this context are the improvement items forplant operation control (such as start-up time, rate of load change,equipment lifetime consumption, fuel cost, and generation efficiency,etc.); they are each defined by the function of a plant process amount.There may be one or a plurality of objective functions to be inputted tothe objective function setting section 1. One way of inputting anobjective function to the objective function setting section 1 is byhaving a list of objective functions stored beforehand in a storagedevice of the control parameter optimizing system 100 and by allowingthe operator to select from the objective function list the objectivefunction to be optimized.

The control parameter optimizing section 2 includes an optimizationcontrol parameter selecting section 7 and an optimization controlparameter adjusting section 8. The optimization control parameterselecting section 7 selects, from the control parameters of the plant ofinterest, the control parameter used to optimize the objective function(called the optimization control parameter hereunder where appropriate).The optimization control parameter adjusting section 8 adjusts the valueof the optimization control parameter selected by the optimizationcontrol parameter selecting section 7.

Based on control logic information manually inputted by the operator orautomatically inputted from an external system, the optimization controlparameter selecting section 7 first extracts the control parametersrelated to the objective function (called the related control parametershereunder where appropriate). The optimization control parameterselecting section 7 then selects from the related control parameters theone having high sensitivity to the objective function as theoptimization control parameter. The optimization control parameterselecting section 7 then outputs the selected optimization controlparameter to the optimization control parameter adjusting section 8. Thesensitivity of each of the related control parameters to the objectivefunctions is obtained through sensitivity analysis using the plant model3.

Described below referring to FIG. 2 are some typical steps forextracting the related control parameters, the steps being performed bythe optimization control parameter selecting section 7. FIG. 2 is aschematic view showing typical control logic information to be inputtedto the optimization control parameter selecting section 7. In FIG. 2,the control logic information 20 is made up of a plurality of controllogic modules 21 to 24 interconnected hierarchically via signal lines.Although there may be control logic modules connected hierarchicallyabove the control logic module 21 or below the control logic module 23or 24, they are omitted for purpose of simplification and illustration.

Extraction Step 1

First, the optimization control parameter selecting section 7 detectsfrom the control logic modules 21 to 24 a signal corresponding to theobjective function (assumed to be the objective function A1 in thisexample) set by the objective function setting section 1. One way ofdetecting such a control signal is by searching the control logicmodules for the signal having the name of a character string identicalor similar to the character string constituting the name of theobjective function. In this example, a signal A1 with a character stringname that matches the character string “A1” of the objective function A1is detected from the control logic module 21. Preferably, the detectedsignal corresponding to the objective function may be displayed on anexternal monitor, for example, so that the operator can verify thedetected signal. If a plurality of signals have been detected, theoperator may be prompted to select the appropriate signal on themonitor. In any case, arrangements can be made to let the signalcorresponding to the objective function be detected in an interactivemanner.

Extraction Step 2

Reference is then made to the control logic module 21 from which thesignal A1 corresponding to the objective function is output. A controlparameter PA1 connected to the signal A1 is extracted as a relatedcontrol parameter. Also, a signal B3 connected to the signal A1 isdetected.

Extraction Step 3

Then reference is made to the control logic module 22 from which thesignal B3 is output. Control parameters PB2 and PB3 connected to thesignal B3 are extracted as related control parameters. Also, signals C2and D1 connected to the signal B3 are detected.

Extraction Step 4

Next, reference is made to the control logic module 23 from which thesignal C2 is output. Control parameters PC1 and PC2 connected to thesignal C2 are extracted as related control parameters. Reference isfurther made to the control logic module 24 from which the signal D1 isoutput. Control parameters PD1 and PD2 connected to the signal D1 areextracted as related control parameters.

Further Steps Omitted

In the manner described above, the control parameters connected to thesignal A1 corresponding to the objective function are detected in ahierarchically retroactive manner on the low-order side of the controllogic modules 21 to 24, whereby the control parameters related to theobjective function A1 (related control parameters) can be extracted.Preferably, information on the correspondence between the objectivefunctions and the previously extracted related control parameters may bestored in a storage device of the control parameter optimizing system100. When the same objective function is set, the correspondenceinformation may be used to extract the related control parameters. Thisallows the extraction steps above to be omitted whenever the sameobjective function is set, shortening the time required to extract therelated control parameters.

From the related control parameters extracted in the above-describedextraction steps, the optimization control parameter selecting section 7selects as the optimization control parameter one or a plurality ofrelated control parameters having high sensitivity to the objectivefunction. The sensitivity of a related control parameter to an objectivefunction is defined, for example, by the ratio of the amount of changein the objective function to the amount of change in the related controlparameter. The degree of the sensitivity of a related control parametercan be obtained by inputting some different values of the relatedcontrol parameter to the plant model 3 and making the plant model 3calculate the objective function for each value. Based on thesensitivity degree obtained from this calculation, the related controlparameters for optimization are selected. Preferably, the relatedcontrol parameters selected as the optimization control parameters maybe displayed on an external monitor, for example, so that the operatorcan verify the selected parameters. Alternatively, a plurality ofrelated control parameters may be displayed in descending order ofsensitivity, so that the operator may be prompted to select theoptimization control parameter. In any case, arrangements can be made tolet the optimization control parameter be detected in an interactivemanner.

The optimization control parameter adjusting section 8 adjusts the valueof the optimization control parameter selected by the optimizationcontrol parameter selecting section 7 in such a manner as to optimizethe objective function set by the objective function setting section 1.The optimization control parameter adjusting section 8 then outputs theadjusted optimization control parameter to an optimization controlparameter setting section 201. The optimization control parameteradjusting section 8 also outputs the optimized objective function(optimum solution) to an external output interface 14. Described belowis a typical procedure for adjusting the value of the optimizationcontrol parameter, the steps being performed by the optimization controlparameter adjusting section 8.

Adjustment Step 1

The optimization control parameter adjusting section 8 first sets apredetermined value to the optimization control parameter selected bythe optimization control parameter selecting section 7. The optimizationcontrol parameter adjusting section 8 then inputs the optimizationcontrol parameter to the plant model 3. The plant model 3 calculates theobjective function based on the value of the optimization controlparameter inputted from the optimization control parameter adjustingsection 8 using a control model 9 and a physical model 10 (both to bediscussed later).

Adjustment Step 2

The optimization control parameter adjusting section 8 adjusts the valueof the optimization control parameter in such a manner as to minimizethe difference between the calculated value of the objective functionoutputted from the plant model 3 and a predetermined target value.

The optimization control parameter adjusting section 8 adjusts theoptimization control parameter value by performing the above-describedadjustment steps once or a number of times. An existing optimizationalgorithm such as the multi-objective evolutionary algorithm or thesuccessive quadratic programming method may be used in adjusting thevalue of the optimization control parameter.

It might happen that at the control panel of the control target plant,the control parameters have no constant values and are each defined bythe function of a plant process amount, for example. In such a case, theabove-described adjustment steps may be performed to obtain anoptimization control parameter value for each of a plurality ofpredetermined process amounts. A function that interpolates these valuesthen may be taken as the optimization control parameter.

From plant control parameter information manually inputted by theoperator or automatically inputted from an external system, the controlparameter setting section 4 extracts the control parameters necessaryfor creating the control model 9 (to be discussed later) in the plantmodel 3. The control parameter setting section 4 sets the extractedcontrol parameters to the control model 9. The control parameterinformation in this context refers to information on the controlparameters stored in the control panel, such as control settings withregard to the controlled amount of the plant, control gain items, theirvalues, and their upper and lower limits. In a variation of thisembodiment, plant control logic information instead of the controlparameter information may be inputted to the control parameter settingsection 4. In this case, the control parameter setting section 4 needsto pattern-recognize the inputted control logic information, suchinformation as signal lines, status symbols and values, and then extractthe items with values in the control logic modules, i.e., controlparameters and their values constituting the control parameterinformation.

From plant characteristic information manually inputted by the operatoror automatically inputted from an external system, the physicalparameter setting section 5 extracts the physical parameters necessaryfor creating the physical model 10 of the plant model 3. The physicalparameter setting section 5 sets the extracted physical parameters tothe physical model 10. The plant characteristic information in thiscontext refers to information on the operational condition of the plant:specifically, the heat balance or mass balance of the plant processamount, or the response speed of the plant process amount to changes inheat load. The plant process amount can be represented by thetemperature, flow rate, or pressure of the steam generated in responseto the heat load on gas turbines or boilers. In a variation of thisembodiment, plant operation data (i.e., measurement items and theirvalues) instead of the plant characteristic information may be inputtedto the physical parameter setting section 5. In this case, the physicalparameter setting section 5 needs to refer to the inputted operationdata (e.g., steam temperature, flow rate, and pressure corresponding tothe heat load), and then extract the values of the physical parametersnecessary for creating the physical model 10.

From plant design information manually inputted by the operator orautomatically inputted from an external system, the design parametersetting section 6 extracts the design parameters necessary for creatingthe physical model 10 of the plant model 3. The design parameter settingsection 6 sets the extracted design parameters to the physical model 10.The plant design information in this context refers to designinformation that is independent of the operational condition of theplant, such as equipment volume and piping length of the plant.

Preferably, if the names of the parameters extracted by the controlparameter setting section 4, physical parameter setting section 5, ordesign parameter setting section 6 do not match those of the parametersregistered in the plant model 3, the registered parameters with theirnames similar to those of the extracted parameters may be displayedalong with the latter in a mutually corresponding manner on an externalmonitor, for example, so that the operator can verify thecorrespondence.

The plant model 3 has the control model 9 and the physical model 10. Thecontrol model 9 simulates the operation of controlling equipment of thecontrol target plant. The physical model simulates the operation ofcontrolled equipment of the control target plant.

The control model 9 is constituted by a table function for converting aplant process amount to a control command value, by a function forgenerating a pulse signal in response to the magnitude relation betweenthe process amount and a predetermined threshold value, or by acombination of these functions. The control model 9 calculates a controlcommand value based on the calculated value of the plant process amountinputted from the physical model 10. The control model 9 then outputsthe calculated control command value to the physical model 10. Also, thecontrol model 9 calculates an objective function based on the plantprocess amount inputted from the physical model 10. The control model 9then outputs the calculated objective function to the optimizationcontrol parameter selecting section 7 and to the optimization controlparameter adjusting section 8.

Preferably, the plant model 3 may have a control model library made of aplurality of control models 9 corresponding to a plurality of differentplant control methods, respectively, and may select the appropriatecontrol model 9 corresponding to the control method of the controltarget plant. This enables the control parameter optimizing system 100to be applicable to a plant operating on a different control method.

The physical model 10 calculates a plant process amount based on thecontrol command value inputted from the control model 9. The physicalmodel 10 then outputs the calculated process amount to the control model9. Specifically, from the inputted control command value, the physicalmodel 10 determines a fuel flow rate, a steam flow rate, and valveopenings corresponding to these flow rates. Given the mass balance andheat balance of the gas and steam at their respective flow rates, thephysical model 10 calculates the temperature, pressure, and flow rate ofthe gas and those of the steam.

Preferably, the plant model 3 may have a physical model library made ofa plurality of physical models 10 corresponding to a plurality ofdifferent plant equipment configurations or plant types, respectively,and may select the appropriate physical model 10 corresponding to theequipment configuration or plant type of the control target plant. Thisenables the control parameter optimizing system 100 to be applicable toa plant of a different equipment configuration or of a different planttype.

FIG. 3 is a block diagram showing a configuration of an operationcontrol optimizing apparatus 101 equipped with the control parameteroptimizing system 100 according to this embodiment. As shown in FIG. 3,the operation control optimizing apparatus 101 equipped with the controlparameter optimizing system 100 is connected to a power plant 300. Thismakes it possible to optimize the objective function designated by theoperator in the operation control of the power plant 300.

The power plant 300 includes a power generating facility 301 thatgenerates power by combusting fuel, a control device 302 that controlsthe power generating facility 301, a control logic database 303, a timeseries signal database 304, and a design information database 305.

The power generating facility 301 is controlled in accordance with thecontrol command values inputted from the control device 302. Measuringdevices are installed at various locations in the power generatingfacility 301. The process amounts measured by these measuring devicesare outputted to the control device 302 and to the time series signaldatabase 304.

In accordance with a control program stored in the control logicdatabase 303, the control device 302 calculates control command valuesbased on the process amounts inputted from the power generating facility301, and then outputs the calculated control command values to the powergenerating facility 301.

The control logic database 303 stores various control logic modules foruse in controlling the power generating facility 301. The control logicdatabase 303 also stores the control program of the control device 302,which is generated based on the control logic modules. The time seriessignal database 304 stores diverse process amounts inputted from thepower generating facility 301. The design information database 305stores the design information on the power plant 300.

The operation control optimizing apparatus 101 includes the controlparameter optimizing system 100, a data input/output section 200, anexternal input interface 13, and the external output interface 14.

The data input/output section 200 performs data input and output betweenthe power plant 300 and the control parameter optimizing system 100. Thedata input/output section 200 includes the optimization controlparameter setting section 201, a control parameter informationextracting section 202, a plant characteristic information extractingsection 203, a plant design information extracting section 204, and acontrol logic information extracting section 205. The control parameterinformation extracting section 202 extracts control logic informationfrom the control logic database 303 in the power plant 300. The controlparameter information extracting section 202 then outputs the extractedcontrol logic information to the control parameter setting section 4.The plant characteristic information extracting section 203 extractsplant characteristic information from the time series signal database304 in the power plant 300. The plant characteristic informationextracting section 203 then outputs the extracted plant characteristicinformation to the physical parameter setting section 5. The plantdesign information extracting section 204 extracts plant designinformation from the design information database 305 in the power plant300. The plant design information extracting section 204 then outputsthe extracted plant design information to the design parameter settingsection 6. The control logic information extracting section 205 extractscontrol logic information from the control logic database 303 in thepower plant 300. The control logic information extracting section 205then outputs the extracted control logic information to the optimizationcontrol parameter selecting section 7. The capability of theoptimization control parameter setting section 201 will be discussedlater.

The control parameter optimizing system 100 calculates the optimizedresult of the objective function (optimum solution and the correspondingoptimization control parameter) based on the information inputted fromthe control parameter information extracting section 202, plantcharacteristic information extracting section 203, plant designinformation extracting section 204, and control logic informationextracting section 205. The control parameter optimizing system 100 thenoutputs the optimized result of the objective function to theoptimization control parameter setting section 201 and to the externaloutput interface 14.

The external input interface 13 outputs the objective function inputtedfrom an external input device 11 to the objective function settingsection 1 of the control parameter optimizing system 100. In thismanner, the operator can designate the objective function desired to beoptimized by operating the external input device 11.

The external output interface 14 outputs to an external output device 12the optimized result of the objective function outputted from thecontrol parameter optimizing section 2 of the control parameteroptimizing system 100. The external output device 12 is configured by adevice that has a screen display capability, such as a personal computer(PC) monitor. In this manner, the operator can verify the optimizedresult of the objective function via the external output device 12.

Described below are the optimum solutions of objective functions in thecase where the control parameter optimizing system 100 is applied to thecontrol operation for the plant's start-up. FIG. 4A shows typicaldisplay of optimum solutions for the case in which start-up time andlifetime consumption are set as the objective functions. At the powerplant, start-up time and lifetime consumption are generally in atrade-off relation with each other. If a known multi-objectiveevolutionary algorithm is adopted, for example, as the optimizationmethod for the optimization control parameter adjusting section 8, aplurality of optimum solutions T1 to T7 for improving start-up time andlifetime in total are calculated with regard to an objective function T0yet to be optimized. When the optimum solutions T1 to T7 as well as theobjective function T0 yet to be optimized are displayed together asshown in FIG. 4A, the operator can verify the improvement of theoptimized objective function.

FIG. 4B shows typical display of optimum solutions for the case in whichstart-up time, lifetime consumption, and fuel cost are set as theobjective functions. If four or more objective functions are set, theymay be divided into groups of up to 3 objective functions whendisplayed. For example, if four objective functions are set, they may bedivided into a group of three objective functions and one objectivefunction, or into two groups of two objective functions each whendisplayed.

Preferably, when a plurality of optimum solutions T1 to T7 arecalculated as a result of optimizing the objective functions as shown inFIG. 4A, a display screen of the external output device 12 may beconfigured to display the operation characteristics of each of theoptimum solutions for verification. This configuration is describedbelow referring to FIG. 5. FIG. 5 shows another typical display of theoptimum solutions for the case in which start-up time and lifetimeconsumption are set as the objective functions. In FIG. 5, a displayscreen 121 of the external output device 12 displays an optimum solutiondisplaying region 122 that displays the optimum solutions of anobjective function, a list displaying region 123 that displays a list ofprocess amounts of the plant, and a time series data displaying region124 that displays time series data of the process amounts. By operatingthe external input device 11, the operator selects one of a plurality ofoptimum solutions T1 to T7 displayed in the optimum solution displayingregion 122 and check-marks one or more process amounts displayed in thelist displaying region 123. This causes the time series data displayingregion 124 to display the time series data of the process amountscheck-marked in the list displaying region 123, the process amountsbeing part of those corresponding to the optimum solution selected inthe optimum solution displaying region 122. This allows the operator toverify the operation characteristics of each of the multiple optimumsolutions T1 to T7.

Returning to FIG. 3, the optimization control parameter setting section201 of the data input/output section 200 sets to the control logicdatabase 303 of the power plant 300 the optimization control parametercorresponding to the optimum solution selected by the operator havingoperated the external input device 11, the optimization controlparameter being part of the optimized result (a plurality of optimumsolutions and their corresponding optimization control parameters)outputted from the control parameter optimizing system 100. If none ofthe multiple optimum solutions is selected by the operator, nooptimization control parameter will be set to the control logic database303. This enables the actual control of the power plant 300 to reflectan appropriate optimum solution that can achieve the desired operationcharacteristics, the appropriate optimum solution being one of themultiple optimum solutions calculated by the control parameteroptimizing system 100.

The above-described control parameter optimizing system 100 according tothis embodiment optimizes objective functions by adjusting the values ofthe control parameters stored in the control logic database 303 of thepower plant 300. Thus when applying the control parameter optimizingsystem 100 to an existing power plant 300, there occurs no need tomodify the control panel or the equipment of the plant 300. And becausethe objective function setting section 1 can be used to set theobjective function desired to be optimized, the operation control of thepower plant 300 can be optimized in accordance with diverse operationalrequirements from the operator.

Further, the optimization control parameter selecting section 7 extractsthe control parameters related to the objective function (i.e., relatedcontrol parameters) from the control logic information 20 of the powerplant 300. The optimization control parameter selecting section 7 thenselects from the related control parameters the control parameter havinghigh sensitivity to the objective function (i.e., optimization controlparameter). This makes it possible to optimize the objective functionmore efficiently than if the control parameters were selected by theoperator based on his or her personal experience. Because the controlparameters of which values need to be adjusted using the plant model 3are limited to the optimization control parameter, the amount of thecalculations using the plant model 3 is minimized.

Also, the control parameter setting section 4 sets to the control model9 the control parameters extracted from the power plant 300. Thephysical parameter setting section 5 and the design parameter settingsection 6 set to the physical model 10 the physical parameters and thedesign parameters, respectively, extracted from the power plant 300. Thesettings create the plant model 3 that faithfully simulates theoperation of the power plant 300. This enables the optimization controlparameter selecting section 7 to improve the accuracy of the selectionand the optimization control parameter adjusting section 8 to enhancethe accuracy of the adjustment.

Furthermore, the operation control optimizing apparatus 101 according tothis embodiment has the data input/output section 200 performing datainput and output between the power plant 300 and the control parameteroptimizing system 100. This eliminates the need for the operator's inputor output operations, thereby reducing the amount of work done by theoperator.

Also, by means of the external output device 12 and external inputdevice 11, the operator can verify the dynamic characteristics of eachof a plurality of optimum solutions calculated by the control parameteroptimizing system 100. This enables the actual control of the powerplant 300 to reflect an appropriate optimum solution that can achievethe desired operation characteristics.

Second Embodiment

FIG. 6 is a block diagram showing a configuration of an operationcontrol optimizing apparatus according to a second embodiment of thepresent invention. In FIG. 6, the operation control optimizing apparatus101A differs from the operation control optimizing apparatus 101according to the first embodiment (FIG. 3) in that the apparatus 101Afurther includes a plant operation limiting value calculating section 15and an optimum solution selecting section 16.

The plant operation limiting value calculating section 15 calculatesplant operation limiting values based on the plant characteristicinformation extracted by the plant characteristic information extractingsection 203 and on the plant design information extracted by the plantdesign information extracting section 204. The plant operation limitingvalue calculating section 15 then outputs the calculated plant operationlimiting values to the optimum solution selecting section 16. The plantoperation limiting values in this context refer to the limiting values(upper or lower limits) on the plant process amounts (e.g., lifetimeconsumption of component devices, temperature, pressure, and rate ofload change).

Described below is a typical procedure performed by the plant operationlimiting value calculating section 15 to calculate a plant operationlimiting value when the plant operation limiting value is defined as thelifetime consumption per start-up of a steam turbine rotor (simplycalled the lifetime consumption hereunder). Using a known fatigue lifeassessment method, the plant operation limiting value calculatingsection 15 first calculates lifetime consumption of the steam turbinerotor based on the heat stress generated in the steam turbine rotorincluded in the plant characteristic information and on the rotormaterial included in the plant design information. The plant operationlimiting value calculating section 15 then calculates the remaininglifetime by subtracting the sum of the lifetime consumption in the pastoperation cycles from the total lifetime of the steam turbine rotor. Theplant operation limiting value calculating section 15 then calculatesthe lifetime consumption by dividing the remaining lifetime by theremaining number of times the turbine is scheduled to be started up.

Out of a plurality of optimum solutions inputted from the controlparameter optimizing section 2, the optimum solution selecting section16 selects the optimum solution that will meet the plant operationlimiting values inputted from the plant operation limiting valuecalculating section 15. The optimum solution selecting section 16 thenoutputs the optimization control parameter corresponding to the optimumsolution to the optimization control parameter setting section 201.

The capability of the optimum solution selecting section 16 is describedbelow in detail referring to FIG. 7. FIG. 7 is a schematic view showinga typical relation between multiple optimum solutions and a plantoperation limiting value for the case in which start-up time andlifetime consumption are set as the objective functions and an upperlimit of the lifetime consumption is set as the plant operation limitingvalue. The optimum solution selecting section 16 selects one of theoptimum solutions T3 to T7 meeting the plant operation limiting value Lfrom among the multiple optimum solutions T1 to T7. FIG. 7 shows anexample in which the optimum solution T3 closest to the plant operationlimiting value L is selected from the optimum solutions T3 to T7 meetingthe limiting value L. There may also be other diverse methods forselecting the optimum solution. For example, from among the optimumsolutions T3 to T7 that meet the plant operation limiting value L, theoptimum solution having a minimum weighted average of start-up time andlifetime consumption may be selected.

The operation control optimizing apparatus 101A according to the secondembodiment provides the same effects as the apparatus of the firstembodiment. In addition, from a plurality of optimum solutionscalculated by the control parameter optimizing section 2, the optimumsolution selecting section 16 selects the optimum solution meeting theplant operation limiting value calculated by the plant operationlimiting value calculating section 15. This eliminates the need for theoperator's selecting operation, thereby reducing the amount of work doneby the operator.

Variations

The present invention is not limited to the above-described embodimentsand may be implemented in diverse variations. For example, although theoperation control optimizing apparatus 101 according to the firstembodiment (refer to FIG. 3) and the operation control optimizingapparatus 101A according to the second embodiment (refer to FIG. 6) eachhave the data input/output section 200 that performs automatic input ofnecessary data from the power plant 300 to the control parameteroptimizing system 100, this is not limitative of the present invention.Alternatively, the operator may manually input the necessary data to thecontrol parameter optimizing system 100.

Preferably, the information to be inputted to the optimization controlparameter selecting section 7, to the control model 9, and to thephysical model 10 may be stored beforehand in a storage device of thecontrol parameter optimizing system 100. When the control parameteroptimizing system 100 is applied to another plant of the same type andof a similar scale and when part of the information to be inputted tothe optimization control parameter selecting section 7, to the controlmodel 9, or to the physical model 10 is found defective or missing, thedefective or missing data may be supplemented with the past inputtedinformation stored in the storage device.

Although the above embodiments were described using examples in whichthe control parameter optimizing system 100 is applied to the controloperation for the plant's start-up, i.e., in which the controlparameters are optimized while the plant is being stopped (beforestart-up), this is not limitative of the present invention.Alternatively, the control parameters may be optimized successivelywhile the plant is in operation, for example.

DESCRIPTION OF REFERENCE CHARACTERS

-   1: Objective function setting section-   2: Control parameter optimizing section-   3: Plant model-   4: Control parameter setting section-   5: Physical parameter setting section-   6: Design parameter setting section-   7: Optimization control parameter selecting section-   8: Optimization control parameter adjusting section-   9: Control model-   10: Physical model-   11: External input device-   12: External output device-   13: External input interface-   14: External output interface-   15: Plant operation limiting value calculating section-   16: Optimum solution selecting section-   20: Control logic information-   21-24: Control logic module-   100: Control parameter optimizing system-   101, 101A: Operation control optimizing apparatus-   121: Display screen-   122: Optimum solution displaying region-   123: List displaying region-   124: Time series data displaying region-   200: Data input/output section-   201: Optimization control parameter setting section-   202: Control parameter information extracting section-   203: Plant characteristic information extracting section-   204: Plant design information extracting section-   205: Control logic information extracting section-   300: Power plant-   301: Power generating facility-   302: Control device-   303: Control logic database-   304: Time series signal database-   305: Design information database

What is claimed is:
 1. A control parameter optimizing system comprising: an objective function setting section that sets an objective function to be optimized in controlling operation of an existing power plant; a plant model that simulates the operation of the existing power plant and calculates a process amount of the existing power plant and a value of the objective function; and a control parameter optimizing section that optimizes values of control parameters of the existing power plant using the plant model in such a manner as to optimize the objective function; wherein the control parameter optimizing section includes: an optimization control parameter selecting section that, based on control logic information extracted from a control logic database of the existing power plant, selects a control parameter from the control parameters as an optimization control parameter that is for use in optimizing the objective function; and an optimization control parameter adjusting section that adjusts a value of the optimization control parameter using the plant model in such a manner as to optimize the objective function.
 2. The control parameter optimizing system according to claim 1, wherein the optimization control parameter selecting section extracts, from the control logic information, control parameters related to the objective function as related control parameters, and then selects the optimization control parameter from the related control parameters.
 3. The control parameter optimizing system according to claim 2, wherein the optimization control parameter selecting section calculates the sensitivity of each of the related control parameters to the objective function using the plant model, and then selects from the related control parameters the optimization control parameter based on a degree of the calculated sensitivity.
 4. The control parameter optimizing system according to claim 2, wherein the optimization control parameter selecting section stores information on the correspondence between the objective function and the related control parameters after selecting the related control parameters, and the optimization control parameter selecting section extracts the related control parameters from the correspondence information when the objective function setting section sets the same objective function.
 5. The control parameter optimizing system according to claim 1, wherein the optimization control parameter adjusting section performs once or a number of times consecutively a process in which a predetermined value is set to the optimization control parameter, and then the optimization control parameter is inputted to the plant model, and then the predetermined value is changed so as to minimize the difference between a predetermined target value and the calculated value of the objective function outputted from the plant model.
 6. The control parameter optimizing system according to claim 1, wherein the plant model includes: a control model that simulates the operation of controlling equipment of the existing power plant; and a physical model that simulates the operation of controlled equipment of the existing power plant; the control model calculates the objective function and a control command value for the physical model based on the plant process amount calculated by the physical model; and the physical model calculates the plant process amount based on the control command value calculated by the control model.
 7. The control parameter optimizing system according to claim 6, wherein the plant model includes: a control model library made of a plurality of the control models corresponding to a plurality of different plant control methods, respectively; and a physical model library made of a plurality of the physical models corresponding to a plurality of different plant configurations or plant types, respectively.
 8. An operation control optimizing apparatus comprising: the control parameter optimizing system according to claim 1; an external output device that displays a plurality of optimum solutions calculated for the objective function by the control parameter optimizing section; and an external input device that, operated by an operator, selects an optimum solution from among the optimum solutions displayed on the external output device, the optimum solution being to be reflected in controlling the operation of the existing power plant.
 9. An operation control optimizing apparatus comprising: the control parameter optimizing system according to claim 1; a plant operation limiting value calculating section that calculates an operation limiting value of the existing power plant based on the plant characteristic information and the plant design information; and an optimum solution selecting section that, from a plurality of optimum solutions calculated by the control parameter optimizing section, selects an optimum solution meeting the operation limiting value as an optimum solution to be reflected in controlling the operation of the existing power plant.
 10. An operation control optimizing apparatus comprising: the control parameter optimizing system according to claim 1; and a data input/output section that performs data input and output between the existing power plant and the control parameter optimizing system; wherein the data input/output section includes: a control logic extracting section that extracts control logic information from a control logic database of the existing power plant, and then outputs the extracted control logic information to the optimization control parameter selecting section; a plant characteristics information extracting section that extracts physical parameter information from a time series signal database of the existing power plant, and then outputs the extracted physical parameter information as a parameter of the plant model to a physical parameter setting section; a design parameter extracting section that extracts design information on the existing power plant from a design information database of the existing power plant, and then outputs the extracted plant design information as a parameter of the plant model to a design parameter setting section; and an optimization control parameter setting section that sets to the control logic database the optimization control parameter outputted from the optimization control parameter adjusting section. 